First off let me geive you alittle background on myself. I have installed XP Home 34 times this years and XP Professional 78 times this year alone. I have no doubt you can install XP Professional with little or no problems. How much RAM does yor computer have. Xp Professional can run with as little as 128mb but it will be oainful and you will not be happy with the results. I suspect this is part of your problem. I have many computer at my home (13 in all) all but one a intel P-III base. I would recommend you upgrade the memory to 512mb of RAM. RAM is cheap and is a excellnt way to increase your peformance. As a matter of personal expirence the problems you are having could be RAM, or lack of, related.
I do not know what king of problems ThorXP had 25 years ago but it was not windows relaed, since Windows 1.0 did not release til late '83. Even if he did Windows of even the mid-90's is vastly different and have little in common other than they are MicroSoft product. All three XP's are very straight forward to install. The most common problem I find with Windows install is forgeting to remove the CD when prompted to do so at reboot. XP has solved this by detecting the presence of any installed OS and prompting you to "Press any key to boot from CD..."
Since you are having an issue of virus' and malware I recommend you not just FORMAT you drive but WIPING it first. They are many products out there to do this ith but the easiest is Active@KillDisk-Drive Wipe Utility
. It is simple and straight forward. It is also free. This proeedure will take upward of 24 to 36 hours to complete, but is the only way to destory all infected files. FORMATTING will leave the files intact. That is why specialize programs can recover FORMATED or DELETED files. One you wipe a drive there will be little if anythng to recover. Not that you would want to.